Power operated knife sharpener



Jan. 29, 1963 R. D. UTHOFF 3,075,322

POWER OPERATED KNIFE SHARPENER Original Filed June 27, 1960 INVENTOR:

A 7' TORNE'VS.

United States Patent. Office 3,075,322 Patented Jan. 29, 1963 3,075,322 POWER OPERATED KNIFE SHARPENER Robert D. Uthotf, Jefferson Qounty, near Fenton, Mo., as-

signor to Knapp-Monarch Company, St. Louis, Mo., a corporation of Delaware I Original application June 27, 1960, Ser. No. 38,819, now Patent No. 3,009,244, dated Nov. 21,1961. Divided and this application Oct. 3, 1960, Ser. No. 60,151

3 Claims. (Cl. 51-128) This invention relates to power operated knife sharpeners and more particularly to ventilating means for cooling the motor of a knife sharpener either as a separate appliance or in combination with a can opener and protecting the motor from ingress of grit or similar foreign particles.

One of the problems encountered in power operated knife sharpeners is preventing grit and similar foreign material resulting from operation of the sharpening wheel from getting into the motor or other moving parts and damaging the same. If the motor or gearing associated therewith is sealed, the construction becomes very expensive and impractical. Furthermore, with the motor and gearing sealed they tend to heat rapidly and must be made of larger capacity than would normally be required for the service involved.

It is therefore an object of the present invention to provide a power operated knife sharpener in which grit and similar foreign material resulting from operation of the sharpening wheel is positively prevented from getting into the motor or other moving parts while adequately ventilating the motor and other parts.

According to a feature of the invention, the sharpening wheel is separated from the motor by a partition having an opening therein and a blower wheel operates closely adjacent to the partition on the sharpening wheel side thereof to draw air through the opening. In this way,

the'current of air opposes passage of grit or similar particles through the opening toward the motor and pasage of such particles is additionally positively blocked by 4 the blower rotor itself.

In one desirable construction the sharpening wheel is combined with a can opener to be driven by the same motor and air is drawn in and ,over the gearing for the can opener drive and over the motor to cool it before passing through the partition into the sharpening wheel compartment.

The above and other objects and features of the invention will be more readily apparent from the following description when read in connection with the accompanying drawing, in which:

FIGURE 1 is a sectional view through a combined can opener and sharpening wheel embodying the invention; and

FIGURE 2 is a transverse section on the broken line 2-2 of FIGURE 1.

This application is a division of my co pending application Serial No. 38,819, filed June 27, 1960, now Patent No. 3,009,244 issued November 21,, 1961 in which the construction of the can opener itself is more particularly disclosed and claimed. For a fuller understanding of the operation of the can opener portions of the combined mechanism reference is therefore made to the co-pending application, this application being directed particularly to features of the sharpening wheel construction.

As shown, the combined structure comprises a hollow casing defined by a horizontal base which may conveniently be supported on legs 11 and to which is secured a vertical front plate indicated generally at 12. The front plate and base receive a hollow molded casing 13 which is preferably of plastic material and which fits against the base and front plate at its edges to define a complete enclosing casing. As seen in FIGURE 1, the casing is generally L-shaped with a vertically elongated compartment 14 and a horizontal elongated compartment 15 joined thereto.

The front plate carries the can cutting mechanism, ineluding a knurled feed wheel 16 and a cutting wheel 17 which is movable toward and away from the feed wheel to grip the rim of a can therebetween and to cut the top closure from the can. A magnet 18 may also be provided carried by a pivoted arm 19 to attract the cut out can top and move it away from the remainder of the can at the completion of a cutting operation. The cutting wheel may be moved toward and away from the feed wheel 16 to can engaging and can releasing positions through mechanism more particularly described and claimed in my co-pending application, but which will not be further described herein since it forms no part of the present invention.

The feed wheel'16 is adapted to be driven by an electric motor 21 which is mounted in the lower part of the vertically elongated compartment 13 of the casing with its axis horizontal. The motor, as shown, may be of a relatively inexpensive open-type construction with a first shaft end 22 extending from one end thereof and a sec- 0nd shaft end 23 extending from the opposite end thereof to be driven when the motor is'energized. The shaft end 22 drives the feed wheel 16 through a system of reducing gearing, including a pinion 24 secured to the shaft end 22 and meshing with the large gear of a double gear 25. The smaller gear of the double gear 25 meshes with the larger gear of a similar double gear 26 whose smallerge'ar meshes with a large gear 27 secured to the shaft for the feed wheel 16. The foregoing gearing constitutes a'reduc tion gearing to turn the feed wheel 16 at relatively low speed and high torque with a standard relatively high speed motor. The gearing, as shown, is supported in pivots carried by the front plate 12 and by a bracket 28 that is secured to the casing, but spaced from the front plate 12 and rigidly connected thereto through supporting arms, not shown. v

The horizontally elongated portion of the casing carries a partition 29 extending vertically therein and separating the compartments 14 and 15. The partition is formed with an enlarged central opening 31 therein through which the shaft end 23 extends centrally. The shaft 23 adjacent to its outer end carries a sharpening wheel 32 and the 'upper portion of the casing is formed with openings 33 through which the blades -'of knives or similar articles to be sharpened may be inserted into sharpening engagement with the wheel- 32. The openings 33, as shown, are

defined by guiding flanges and edges which may be integrally molded with the casing part 13 to guide the blade of a knife correctly for proper sharpening thereof against the wheel 32.- I i To cool the motor and other parts, a blower wheel, indicated generally at 34, is secured to theshaft 23-between the sharpening wheel 32 and the partition 29 and closely adjacent to the partition. The blower'wheel, as

shown, includes a series of radially extendingblades 35,

adjacent to the partition 29' and'of a-larg'er radial extent than the partition opening- 31, and a backing disc-36secured to the edges'of'the'blades that are spaced remotely from the partition. The disc 36 is also of larger diameter than the opening 31 in the partition.

The blower wheel is adapted to circulate air through the entire casing to ventilate and cool the several parts therein. For this purpose the casing part 13 is formed with a series of louvered inlet openings 37 near the top thereof through which air may flow into the vertically elongated compartment 14. The air may be discharged through vent openings 38 formed in the base 10, as best seen in FIGURE 2, and which may be partially shielded by the lower edges of the casing part 13 so that air will be discharged downwardly therefrom. Some of the air discharged from the casing may flow through the openings 33, but it is contemplated that the major portion thereof will be discharged through the vent openings 38.

When the motor is running for either a can-opening or knife sharpening operation the blower wheel 34 will draw airinto the casing through the openings 37 and over the drive gearing and the motor 21 to ventilate and cool the same. The air will then flow through the opening 31 in the partition 29 and be discharged outwardly by the blades 35 around the periphery of the disc 36'. The major portion of the air will be discharged directly through the vent openings 38 with some minor portion thereof possibly escaping through the openings 33.

During a knife-sharpening, or other grinding or sharpening operation, a certain amount of grit and similar foreign particles will be generated by the sharpeningwheel 32. If this material were allowed to get into the motor or into any of the principal bearings for the motor or gearing, it would obviously result in serious damage thereto. By the present invention, such grit and similar material is positively excluded from the compartment 14 in which the gearing and motor are housed and is retained in the sharpening wheel compartment until it is discharged from the casing along with the air through the vent opening 38. This is partially accomplished due to the 'fact that the flow of air is from the motor compartment 14 through the partition opening 31 into the sharpening wheel compartment 15, but principally due to the positioning and operation of the blower wheel 34 itself, It will be seen that any grit or other particles generated by thesharpening wheel must pass around the periphery of the disc 36 and'radially inward over the radial blades 35 to reach the opening 31 in the partition. When the blower wheel 34 is turning, the centrifugal action of the disc and blades will positively prevent any movement ofsuch grit or particles so that they are positively and completely excluded from the compartment '14 in which the motor and gearing are housed. Therefore, open gearing and the open motor 21 may be utilized in the present construction without requiring any sealing and without any possibility of damage due to grit or the like from the sharpening wheel 32. All seals and gaskets which would 'notonly add to the expense of the unit but would impose frictionaldrag on the rotating parts are eliminated, so

ment, thepartition having a central opening therethrough,

a motor in the motor compartment having a shaft extend ing through the opening and into the sharpening wheel compartment, a blower wheel in the sharpening wheel compartment secured to the shaft adjacent to the partition to draw air'through the opening in the partition and discharge it into the sharpening wheel compartment, said casing having a vent opening therein below a horizontal plane passing through the shaft, said vent opening being adjacent the periphery of the blower wheel so that air may be discharged through said vent opening from the sharpening wheel compartment, and a sharpening wheel secured to the shaft beyond the blower wheel, the casing having an opening therein through which a knife to be sharpened may be inserted to engage the sharpening wheel.

2. A power operated knife sharpener comprising a hollow casing, a partition in the casing separating it into a motor compartment and a sharpening wheel compartment, the partition having a central opening therethrough, a motor in the motor compartment having a shaft extending through the opening and into the sharpening wheel compartment, a blower wheel in the sharpening wheel compartment secured to the shaft including a series of radially extending blades adjacent to the partition and an imperforate disc secured to the edges of the blades remote from the partition and of larger diameter than the opening in the partition, and a sharpening wheel "secured to the shaft beyond the disc, there being an opening in the casing through which a knife can be inserted 'to engage the wheel, and there being a vent opening in the casing adjacent the periphery of the blower wheel and below a horizontal plane passing through the axis of the shaft through which vent opening air and particles may be discharged from the sharpening wheel compartment.

3. A power operated knife sharpener comprising a hollow L-shaped casing having a vertically elongated section and a horizontally elongated section, a vertical partition in the horizontally elongated section adjacent to the junction thereof with the vertically elongated section and having a central opening therein, a motor in the lower part of the vertically elongated section having shafts extending horizontally from opposite ends thereof, one of the shafts extending through the opening into the horizontally elongated section, gearing in the vertically elongated section adapted for driving an appliance drivably connected to the other shaft, a blower wheel secured to said one of the shafts and lying in the horizontally elongated section closely adjacent to the partition and with said partition spaced between the motor and the blower wheel, and a sharpening wheel secured to said one of the shafts beyond the blower wheel so that the blower wheel is spaced between said motor and said sharpening wheel, there being openings in the upper part of the vertically elongated section and in the horizontally elongated section beyond the partition, one of 'said openings in said horizontal section being adjacent said blower wheel in the lower portion of the horizontal section and comprising a vent opening, whereby the blower wheel will draw air into and through the vertically elongated section over the gearing and motor therein and through the opening in the partition for discharge primarily through said vent opening in said horizontal section adjacent said blower wheel.

References Cited in the file of this patent UNITED STATES PATENTS 2,'722;7s3 ORu'ssa Nov. '8, 1955 2,775,075 McMa's'ter Dec. 25, 1956 2,897,637 Bodle Aug. 4, 1959 

1. A POWER OPERATED KNIFE SHARPENER COMPRISING A HOLLOW CASING, A PARTITION IN THE CASING SEPARATING IT INTO A MOTOR COMPARTMENT AND A SHARPENING WHEEL COMPARTMENT, THE PARTITION HAVING A CENTRAL OPENING THERETHROUGH, A MOTOR IN THE MOTOR COMPARTMENT HAVING A SHAFT EXTENDING THROUGH THE OPENING AND INTO THE SHARPENING WHEEL COMPARTMENT, A BLOWER WHEEL IN THE SHARPENING WHEEL COMPARTMENT SECURED TO THE SHAFT ADJACENT TO THE PARTITION TO DRAW AIR THROUGH THE OPENING IN THE PARTITION AND DISCHARGE IT INTO THE SHARPENING WHEEL COMPARTMENT, SAID CASING HAVING A VENT OPENING THEREIN BELOW A HORIZONTAL PLANE PASSING THROUGH THE SHAFT, SAID VENT OPENING BEING ADJACENT THE PERIPHERY OF THE BLOWER WHEEL SO THAT AIR MAY BE DISCHARGED THROUGH SAID VENT OPENING FROM THE SHARPENING WHEEL COMPARTMENT, AND A SHARPENING WHEEL SECURED TO THE SHAFT BEYOND THE BLOWER WHEEL, THE CASING HAVING AN OPENING THEREIN THROUGH WHICH A KNIFE TO BE SHARPENED MAY BE INSERTED TO ENGAGE THE SHARPENING WHEEL. 